A Reduction In Hepatic Lipid Markers In Response To Aerobic Exercise In Obese Individuals With Nafld

Hepatic lipoprotein kinetics are common metabolic complications associated with nonalcoholic fatty liver disease (NAFLD) and obesity. Physical activity and weight loss have been recommended to improve NAFLD and its metabolic derangements. However, the effect of regular physical activity, independent of weight loss, on NAFLD is not known. PURPOSE: The purpose of this study was to determine the effects of moderate-intensity endurance exercise training (225 min per week) on intrahepatic triglyceride content (IHTG) content and very-low-density lipoprotein (VLDL) kinetics in obese subjects with NAFLD. METHODS: Twenty-four obese individuals (BMI=37.1±3.6 kg/m2) with NAFLD (IHTG 19.9±2.1%) were randomized to 16 weeks of exercise training (45-55% O2peak, 45 min x 5 days/week; n=12) or observation (control; n=12). Exercise-induced weight loss was prevented by providing liquid formula dietary supplements. Magnetic resonance spectroscopy and stable isotope tracer infusions in conjunction with compartmental modeling were used to evaluate IHTG content and hepatic VLDL-TG and apolipoprotein B-100 (apoB-100) secretion rates. RESULTS: As expected there was no change in body weight (101.9±3.2 kg and 102.3±3.2 kg before and after training). IHTG was significantly (p<0.05) reduced by 10.3±4.6% in the exercise group with no significant change (1.3±1.6%) in the control group. Exercise training significantly reduced VLDL-TG secretion rate (18.7±2.9 μmol/min and 15.8±3.4 μmol/min before and after training) and VLDL-apoB-100 secretion rate (1.9±0.4 nmol/min and 1.2±0.3 nmol/min before and after training). CONCLUSIONS: Moderate intensity aerobic exercise, independent of weight loss, had beneficial effects on IHTG and hepatic lipoprotein kinetics, in obese individuals with NAFLD.